Choroid development and feasibility of choroidal imaging in the preterm and term infants utilizing SD-OCT

LONGITUDINAL CHANGES IN CHOROIDAL THICKNESS IN CHILDREN WITH A HISTORY OF PREMATURITY: An 18-Month Prospective Cohort Study

PURPOSE

To evaluate choroidal changes over time in school-age children with a history of prematurity.

METHODS

A study of 416 eyes of 208 eligible participants, including 88, 190, 36, 56, and 46 eyes in the full-term control, preterm, spontaneously regressed retinopathy of prematurity, intravitreal bevacizumab (injection of bevacizumab)-treated retinopathy of prematurity, and laser-treated retinopathy of prematurity groups, respectively, were enrolled in this study. The choroidal thickness was measured 4 times at 6-month intervals using optical coherence tomography.

RESULTS

Of all the groups, the laser-treated children had the thinnest choroid compared with full-term children (-52.3 µ m, P = 0.04). Preterm children exhibited greater attenuation in choroidal thickness over time than did full-term children (-6.3 ± 26.9 and -1.1 ± 12.8 µ m/year, P = 0.03), whereas no difference was observed between injection of bevacizumab and laser treatments (-4.6 ± 18.9 and -2.0 ± 15.7 µ m/year, P = 0.46). In all groups, the changes in axial length were negatively associated with the changes in choroidal thickness (all P < 0.05).

CONCLUSION

A greater attenuation in choroid thickness over time was observed in preterm children than in full-term children, but this attenuation did not differ between injection of bevacizumab and laser treatments. Axial elongation was associated with choroidal thinning in school-age children.

Choroidal measurements in decision making for retinopathy of prematurity: a decision tree analysis

BACKGROUND

To compare the choroidal thickness and vascular profile of premature infants with ROP (retinopathy of prematurity) using a handheld SD-OCT device.

METHODS

We performed horizontal SD-OCT scans through the fovea in 115 eyes of 66 premature infants. Premature infants included 2 groups [infants with ROP requiring treatment (as treatment group) vs. infants without ROP or with ROP not- requiring treatment (as no-treatment group)] Choroidal thicknesses (CT) were measured at 5 points, including the fovea, 250 µm, and 500 µm mm nasal and temporal to the fovea. The choroidal vascularity index (CVI) and choroidal stromal index (CSI) were also calculated. The classification and regression tree (CRT) algorithm was used to predict the need for treatment based on all OCT characteristics.

RESULTS

Mean CT was higher in 500 µm nasal to the fovea compared to temporal CT (275.8 ± 64.8 and 257.1 ± 57.07, P value < 0.03). No statistically significant difference was found regarding CVI, corrected CVI, and temporal and nasal CT in the treatment group versus the no-treatment group. The foveal CT was significantly lower in ROP patients with the plus disease compared to not-plus ROP (P value = 0.03. ANOVA, Bonferroni posthoc test). CT was not significantly different between plus and pre-plus patients (P-value = 0.9, ANOVA, Bonferroni posthoc test). No significant relationship was found between the stage of ROP and choroidal thickness (P value > 0.05, GEE). The decision tree analysis showed that in infants with ROP, the most important predictor for the need for treatment is CSI.

CONCLUSION

This study delineated the possible effectiveness of choroidal measurements as an additive to decision-making for ROP. We also demonstrated that choroidal involution is associated with the presence of plus disease, not with the stage of ROP. We demonstrated that choroidal measurements are very sensitive but not specific tools for assessing the need for treatment in ROP patients.

[Anatomo-functional state of the central retina in premature infants with intraventricular hemorrhage and retinopathy of prematurity]

OBJECTIVE

Assessment of the anatomo-functional state of the central retina in children with intraventricular hemorrhage (IVH) and retinopathy of prematurity (ROP) in the long-term period.

MATERIAL AND METHODS

We examined 51 patients (102 eyes) born 25-34 weeks' of gestation (birth weight 700-2290 g), aged 8.83±3.5 years, and 18 children (36 eyes) born prematurely aged 10.8±3.2 years. The children underwent standard ophthalmologic examination, optical coherence tomography (OCT) and visual evoked potentials (VEP).

RESULTS

Retinal thickness (RT) and retinal volume (RV) in the fovea of premature infants with PH and/or IVH are significantly higher than in healthy full-term infants, which correlates with lower visual acuity (p<0.05). RT and RV in the fovea has an inverse proportional relationship with gestational age (GA), (p<0.05). According to the results of VEP, moderate organic changes in the conduction tract of the visual analyzer are noted in 45% of premature infants (p<0.05).

CONCLUSION

The process of macula formation is affected by many perinatal and postnatal factors, namely: GA, birth weight, ROP, hypoxic-ischemic CNS diseases, and refractive disorders.

Longitudinal Choroidal Development in Preterm Infants

Purpose

To characterize changes in subfoveal choroidal thickness in preterm infants from 30 to 60 weeks' postmenstrual age (PMA).

Design

The prospective, observational Study of Eye Imaging in Preterm infantS (BabySTEPS) enrolled infants eligible for retinopathy of prematurity screening per the American Association of Pediatrics guidelines.

Subjects

Infants imaged with an investigational, handheld OCT at ≥ 4 distinct imaging sessions between 30 to 60 weeks' PMA as part of BabySTEPS.

Methods

Average choroidal thickness across the central subfoveal 1 mm in each eye at each time point was measured using custom segmentation software, and errors were manually corrected by a trained grader. We prospectively collected birth history data. A segmented mixed model was used to analyze the change in choroidal thickness as a function of PMA, birth weight, and gestational age (GA).

Main Outcome Measures

Characterization of normative subfoveal choroidal thickness values and choroidal growth rate between 30 to 60 weeks' PMA.

Results

We included 592 imaging sessions of 79 preterm infants (152 eyes). Mean (± standard deviation) GA was 27.5 ± 2.5 weeks. Mean choroidal thickness was 141.4 ± 34.5 μm at 30 weeks, 272.2 ± 83.9 μm at 38 weeks, and 306.2 ± 77.4 μm between 56 and 60 weeks. Between 30 and 60 weeks' PMA, choroidal growth followed a biphasic model, with a linear growth rate of 14.8 μm per week (95% confidence interval [CI], 13.6-16.0) from 30 until 38.4 weeks, then cessation of growth, with a growth rate of 0.3 μm per week (95% CI, -1.1 to 1.6) from 38.4 to 60 weeks. Infants with extremely low birth weight (ELBW; < 1000 g) and extremely preterm (GA < 28 weeks) infants had significantly slower initial growth rates compared with very low and low birth weight and very preterm and preterm infants (ELBW 13.0 vs. 21.0 μm per week; P < 0.0001 and extremely preterm 13.2 vs. 18.0 μm per week; P = 0.003).

Conclusions

Preterm infant choroidal thickness experiences rapid linear growth from 30 to 38 weeks' PMA, at which time growth nearly stops. These foundational measurements and identification of the impact of extremes of low birth weight and prematurity on choroidal development will be essential as researchers begin to understand the role of choroidal development in ocular and retinal health in human infants.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Preterm infant retinal OCT markers of perinatal health and retinopathy of prematurity

The increasing survival of preterm infants has led to the importance of improving long-term outcomes associated with preterm birth. Antenatal and perinatal insults not only impact mortality, but also long-term disability. While in the intensive care nursery, preterm infants are also exposed to various stressors that lead to long-term cognitive deficits. It is therefore critical to identify early, low-stress, non-invasive biomarkers for preterm infant health. Optical coherence tomography (OCT) is a powerful imaging modality that has recently been adapted to the infant population and provides noninvasive, high-resolution, cross-sectional imaging of the infant eye at the bedside with low stress relative to conventional examination. In this review we delve into discussing the associations between preterm systemic health factors and OCT-based retinal findings and their potential contribution to the development of non-invasive biomarkers for infant health and for retinopathy of prematurity (ROP).

Ocular Pigmentation Impact on Retinal Versus Choroidal Optical Coherence Tomography Imaging in Preterm Infants

Purpose

To evaluate the association of fundus pigmentation with the visibility of retinal versus choroidal layers on optical coherence tomography (OCT) in preterm infants.

Methods

For infants enrolled in BabySTEPS, ophthalmologists recorded fundus pigmentation (blond, medium, or dark) at the first retinopathy of prematurity (ROP) examination. Bedside OCT imaging was performed at each examination, and a masked grader evaluated all OCT scans from both eyes of each infant for visibility (yes/no) of all retinal layers and of the chorio-scleral junction (CSJ). Multivariable logistic regression was used to assess associations between fundus pigmentation and visibility of all retinal layers and CSJ, controlling for potential confounders (i.e., birth weight, gestational age, sex, OCT system, pupil size, and postmenstrual age at imaging).

Results

Among 114 infants (mean birth weight, 943 grams; mean gestational age, 27.6 weeks), 43 infants (38%) had blond, 56 infants (49%) had medium, and 15 infants (13%) had dark fundus pigmentation. Of 1042 scans, all retinal layers were visible in 977 (94%) and CSJ in 895 (86%). Pigmentation was not associated with retinal layer visibility (P = 0.49), but medium and dark pigmentation were associated with decreased CSJ visibility (medium: odds ratio [OR] = 0.34, P = 0.001; dark: OR = 0.24, P = 0.009). For infants with dark pigmentation, retinal layer visibility increased (OR = 1.87 per week; P ≤ 0.001) and CSJ visibility decreased (OR = 0.78 per week; P = 0.01) with increasing age.

Conclusions

Although fundus pigmentation was not associated with the visibility of all retinal layers on OCT, darker pigmentation decreased CSJ visibility, and this effect increased with age.

Translational Relevance

The ability of bedside OCT to capture retinal layer microanatomy in preterm infants, regardless of fundus pigmentation, may represent an advantage over fundus photography for ROP telemedicine.

Vitreoretinal biomarkers of retinopathy of prematurity using handheld optical coherence tomography: a review

Retinopathy of prematurity (ROP) is caused by abnormal retinal vascularization in premature infants that has the potential for severe long-term vision impairment. Recent advancements in handheld optical coherence tomography (OCT) have enabled noninvasive, high-resolution, cross-sectional imaging of the infant eye at the bedside. The use of handheld OCT devices in the diagnosis of ROP in premature infants has furthered our understanding of disease state and progression. This review discusses the known and novel biomarkers of ROP severity in premature infants identified through handheld OCT and potential for future directions.

Multivariate Models to Diagnose Early Referral-Warranted Retinopathy of Prematurity With Handheld Optical Coherence Tomography

Purpose

The purpose of this study was to create multivariate models predicting early referral-warranted retinopathy of prematurity (ROP) using non-contact handheld spectral-domain optical coherence tomography (OCT) and demographic data.

Methods

Between July 2015 and February 2018, infants ≤1500 grams birth weight or ≤30 weeks gestational age from 2 academic neonatal intensive care units were eligible for this study. Infants were excluded if they were too unstable to participate in ophthalmologic examination (2), had inadequate image quality (20), or received prior ROP treatment (2). Multivariate models were created using demographic variables and imaging findings to identify early referral-warranted ROP (referral-warranted ROP and/or pre-plus disease) by routine indirect ophthalmoscopy.

Results

A total of 167 imaging sessions of 71 infants (45% male infants, gestational age 28.2+/-2.8 weeks, and birth weight 995.6+/-292.0 grams) were included. Twelve of 71 infants (17%) developed early referral-warranted ROP. The area under the receiver operating characteristic curve (AUC) was 0.94 for the generalized linear mixed model (sensitivity = 95.5% and specificity = 80.7%) and 0.83 for the machine learning model (sensitivity = 91.7% and specificity = 77.8%). The strongest variables in both models were birth weight, image-based Vitreous Opacity Ratio (an estimate of opacity density), vessel elevation, and hyporeflective vessels. A model using only birth weight and gestational age yielded an AUC of 0.68 (sensitivity = 77.3% and specificity = 63.4%), and a model using only imaging biomarkers yielded 0.88 (sensitivity = 81.8% and specificity = 84.8%).

Conclusions

A generalized linear mixed model containing handheld OCT biomarkers can identify early referral-warranted ROP. Machine learning produced a less optimal model.

Translational Relevance

With further validation, this work may lead to a better-tolerated ROP screening tool.

Semi-Automated Analysis of Foveal Maturity in Premature and Full-Term Infants Using Handheld Swept-Source Optical Coherence Tomography

Purpose

To develop a semi-automated method of measuring foveal maturity using investigational handheld swept source-optical coherence tomography (SS-OCT).

Methods

In this prospective, observational study, full-term newborns and preterm infants undergoing routine retinopathy of prematurity screening were imaged. Semi-automated analysis measured foveal angle and chorioretinal thicknesses at the central fovea and average two-sided parafovea by three-grader consensus, correlating with OCT features and demographics.

Results

One hundred ninety-four imaging sessions from 70 infants were included (47.8% girls, 37.6 ± 3.4 weeks postmenstrual age, 26 preterm infants with birth weight 1057 ± 325.0, gestational age 29.0 ± 3.0 weeks). Foveal angle (96.1 ± 22.0 degrees) steepened with increasing birth weight (P = 0.003), decreasing inner retinal layer thickness, and increasing gestational age, postmenstrual age, and foveal and parafoveal choroidal thickness (all P < 0.001). Inner retinal fovea/parafovea ratio (0.4 ± 0.2) correlated with increasing inner foveal layers, decreasing postmenstrual age, gestational age, and birth weight (all P < 0.001). Outer retinal F/P ratio (0.7 ± 0.2) correlated with ellipsoid zone presence (P < 0.001), increased gestational age (P = 0.002), and birth weight (P = 0.003). Foveal (447.8 ± 120.6 microns) and parafoveal (420.9 ± 109.2) choroidal thicknesses correlated with foveal ellipsoid zone presence (P = 0.007 and P = 0.01, respectively), postmenstrual age, birth weight, gestational age, and decreasing inner retinal layers (all P < 0.001).

Conclusions

Foveal development is dynamic and partially observed through semi-automated analysis of handheld SS-OCT imaging.

Translational Relevance

Semi-automated analysis of SS-OCT images can identify measures of foveal maturity.

Insights into the developing fovea revealed by imaging

Early development of the fovea has been documented by histological studies over the past few decades. However, structural distortion due to sample processing and the paucity of high-quality post-mortem tissue has limited the effectiveness of this approach. With the continuous progress in high-resolution non-invasive imaging technology, most notably optical coherence tomography (OCT) and OCT angiography (OCT-A), in vivo visualization of the developing retina has become possible. Combining the information from histologic studies with this novel imaging information has provided a more complete and accurate picture of retinal development, and in particular the developing fovea. Advances in neonatal care have increased the survival rate of extremely premature infants. However, with enhanced survival there has been an attendant increase in retinal developmental complications. Several key abnormalities, including a thickening of the inner retina at the foveal center, a shallower foveal pit, a smaller foveal avascular zone, and delayed development of the photoreceptors have been described in preterm infants when compared to full-term infants. Notably these abnormalities, which are consistent with a partial arrest of foveal development, appear to persist into later childhood and adulthood in these eyes of individuals born prematurely. Understanding normal foveal development is vital to interpreting these pathologic findings associated with prematurity. In this review, we first discuss the various advanced imaging technologies that have been adapted for imaging the infant eye. We then review the key events and steps in the development of the normal structure of the fovea and contrast structural features in normal and preterm retina from infancy to childhood. Finally, we discuss the development of the perifoveal retinal microvasculature and highlight future opportunities to expand our understanding of the developing fovea.

Association Between Retinal Microanatomy in Preterm Infants and 9-Month Visual Acuity

Importance

Preterm infants are at risk for poor visual acuity (VA) outcomes, even without retinal problems on ophthalmoscopy. Infant retinal microanatomy may provide insight as to potential causes.

Objective

To evaluate the association between preterm infant retinal microanatomy and VA at 9 months' corrected age.

Design, Setting, and Participants

This prospective observational study took place from November 2016 and December 2019 at a single academic medical center and included preterm infants enrolled in Study of Eye Imaging in Preterm Infants (BabySTEPS). Infants were eligible for enrollment in BabySTEPS if they met criteria for retinopathy of prematurity (ROP) screening, were 35 weeks' postmenstrual age or older at the time of first OCT imaging, and a parent or guardian provided written informed consent. Of 118 infants enrolled in BabySTEPS, 61 were included in this analysis. Data were analyzed from March to April 2021.

Exposures

Bedside optical coherence tomography (OCT) imaging at a mean (SD) 39.85 (0.79) weeks' postmenstrual age and monocular grating VA measurement at 9 months' corrected age.

Main Outcomes and Measures

Presence and severity of macular edema and presence of ellipsoid zone at the fovea measured by extracting semiautomated thicknesses of inner nuclear layer, inner retina, and total retina at the foveal center; choroid across foveal 1 mm; and retinal nerve fiber layer (RNFL) across the papillomacular bundle (PMB). Pearson correlation coefficients were calculated and 95% CIs were bootstrapped for the association between retinal layer thicknesses and continuous logMAR VA. Associations were analyzed between retinal microanatomy and normal (3.70 cycles/degree or greater) vs subnormal grating VA at 9 months' corrected age using logistic regression and with logMAR VA using linear regression, adjusting for birth weight, gestational age, and ROP severity at the time of OCT imaging and accounting for intereye correlation using generalized estimating equations.

Results

The mean (SD; range) gestational age of included infants was 27.6 (2.8; 23.0-34.6) weeks, and mean (SD; range) birth weight was 958.2 (293.7; 480-1580) g. In 122 eyes of 61 infants, the correlations between retinal layer thicknesses and logMAR VA were as follows: r, 0.01 (95% CI, -0.07 to -0.27) for inner nuclear layer; r, 0.19 (95% CI, 0.01 to 0.35) for inner retina; r, 0.15 (95% CI, -0.02 to 0.31) for total retina; r, -0.22 (95% CI, -0.38 to -0.03) for choroid; and r, -0.27 (95% CI, -0.45 to 0.10) for RNFL across the PMB. In multivariable analysis, thinner RNFL across the PMB (regression coefficient, -0.05 per 10-μm increase in RNFL thickness; 95% CI, -0.10 to -0.01; P = .046) and prior ROP treatment (regression coefficient, 0.33 for ROP treatment; 95% CI, 0.11 to 0.56; P = .003) were independently associated with poorer 9-month logMAR VA.

Conclusions and Relevance

In preterm infants, RNFL thinning across the PMB was associated with poorer 9-month VA, independent of birth weight, gestational age, need for ROP treatment, and macular microanatomy. Evaluation of RNFL thickness using OCT may help identify preterm infants at risk for poor vision outcomes.

OCT Imaging in Infants

Optical coherence tomography (OCT) is widely applied in diagnosis and management of retina diseases particularly macular diseases in adult retina practices. However, it has been under-utilized in pediatric retinal diseases especially in neonates and infants. Utilization of OCT in primary macular diseases in this age group is also uncommon and is less reported. Challenges involved in image acquisition and limitations with available devices technique can explain the limited research and accurate data availability in the literature in this field. Purpose of this review article is to summarize the use of OCT and its importance in various infantile retinal pathologies such as vascular diseases, tumors, retinal dystrophies, and optic nerve pathologies with primary focus on neonates and infants, along with infant choroid. In addition, we also discuss about future directions including OCT angiography for infants.

Early Postnatal Oxygen Exposure Predicts Choroidal Thinning in Neonates

Purpose

To evaluate whether choroidal thickness (CT) using arm-mounted optical coherence tomography (OCT) in infants screened for retinopathy of prematurity (ROP) correlates with oxygen exposure in neonates.

Methods

OCT images were obtained in infants screened for ROP in a single level IV neonatal intensive care unit. CT was measured at three different locations: the subfoveal center and 1.5 mm from the fovea center in each direction. Correlation and regression analyses were performed to determine the relationship between clinical factors and CT. Clinical factors included gestational age, birth weight, presence of bronchopulmonary dysplasia (BPD), and fraction of inspired oxygen (FiO₂) at defined time points: 30 weeks postmenstrual age (PMA), 36 weeks PMA, and on day of imaging.

Results

Mean subfoveal, nasal, and temporal choroidal thicknesses CT (SFCT, NCT, and TCT, respectively) were 228.0 ± 51.4 µm, 179.7 ± 50.3 µm, and 186.4 ± 43.8 µm, respectively. SFCT was found to be significantly thicker than NCT and TCT (P < 0.0001 and P = 0.0002, respectively), but no significant difference was found between NCT and TCT (P = 0.547). Compared with infants without BPD, infants with BPD had thinner SFCT and NCT (P = 0.01 and P = 0.0008, respectively). Birth weight was positively correlated with SFCT (r = 0.39, P = 0.01) and NCT (r = 0.33, P = 0.045) but not TCT. Gestational age and ROP stage were not significantly associated with CT. SFCT was found to be significantly thinner with higher average FiO₂ supplementation levels at 30 weeks PMA (r = –0.51, P = 0.01) but not at 36 weeks PMA. Regression analysis revealed that FiO₂ at 30 weeks PMA was an independent predictor of SFCT in infants screened for ROP (P = 0.01).

Conclusions

Early postnatal exposure (<32 weeks PMA) to higher oxygen supplementation in premature neonates statistically predicts choroidal thinning.

Systemic Factors Associated with a Thinner Choroid in Preterm Infants

Purpose

To identify systemic health factors associated with a thinner choroid, which has been hypothesized as a cause of poor visual outcomes in low–birth weight infants.

Design

The prospective, observational Study of Eye Imaging in Preterm Infants (BabySTEPS) enrolled infants recommended for retinopathy of prematurity screening based on the American Association of Pediatrics guidelines.

Participants

Infants who underwent imaging with investigational handheld OCT at 36 ± 1 weeks’ postmenstrual age (PMA) as part of BabySTEPS.

Methods

Average choroidal thickness was measured across the central subfoveal 1 mm. We concurrently collected maternal and infant clinical health data. Univariate and multivariate linear regression analyses were performed to evaluate factors associated with choroidal thickness. The left and right eyes showed similar thicknesses, so their average was used for analysis.

Main Outcomes Measures

Association between infant health factors and subfoveal choroidal thickness.

Results

Subfoveal choroidal thickness was measurable in 82 of 85 infants and 94% of eyes. Mean choroidal thickness was 231 ± 78 μm. In the univariate analysis, a thinner choroid was associated with decreased growth velocity (P < 0.001), lower birth weight (P < 0.001), smaller head circumference (P < 0.001), younger gestational age (P = 0.01), the presence of patent ductus arteriosus (P = 0.05), sepsis or necrotizing enterocolitis (P = 0.03), bronchopulmonary dysplasia (P = 0.03), pulmonary interstitial emphysema (P = 0.002), more days on oxygen support (P < 0.001), and being on oxygen support at 36 weeks (P < 0.001) and at the time of imaging (P < 0.001). In the multivariate analysis, growth velocity (P = 0.002) and oxygen support at the time of OCT imaging (P = 0.004) remained associated with a thinner choroid.

Conclusions

A thinner choroid is associated independently with growth velocity and receiving oxygen support at 36 ± 1 weeks PMA. This suggests that choroidal development in preterm infants may be related to growth rate in the first weeks of life and the prolonged use of supplemental oxygen. Longitudinal studies are needed to assess differences in choroidal thickness before 36 weeks PMA and to assess their impact on visual outcomes.

Effect of gestational age at birth, sex, and race on foveal structure in children

PURPOSE

Premature birth, race, and sex are contributing risk factors for retinopathy of prematurity (ROP) and have long-term impact on children's retinal structure. Few studies investigate impact of race and sex on macular structure in children born preterm. This study compared foveal structure in preterm and full-term children.

METHODS

Children aged 4-18 years were enrolled into three groups: (1) ROP-risk group (n = 81), born at < 32 weeks gestational age with and without history of ROP; (2) preterm group (n = 46), born at 32-36 weeks gestational age; and (3) control group (n = 68) with full-term birth. Using spectral-domain optical coherence tomography volume-scan images, foveal structure within 1-mm and 3-mm early treatment diabetic retinopathy study circular grid was measured and segmented. Total inner and outer retina thickness of the right eye was compared among the three groups.

RESULTS

The mean total foveal thickness (in microns) was 287 ± 26 for the ROP-risk group, 276 ± 19 for the preterm group, and 263 ± 20 for the control group (F = 26, p < 0.001). Foveal thickness of the ROP-risk group was significantly higher than that of the preterm group and the control group (all p < 0.05). Foveal thickness was thinner in black children than in white children and thinner in females than in males (all p < 0.001). A similar disparity in race and sex was found in the thickness of the inner and outer layers.

CONCLUSIONS

The fovea was significantly thicker in the ROP-risk group than the control group. Foveal thickness decreases with increased gestational age. Race and sex are significant factors in foveal structure in children.

Evaluating the association of clinical factors and optical coherence tomography retinal imaging with axial length and axial length growth among preterm infants

PURPOSE

To study the association of clinical factors and optical coherence tomography (OCT) retinal imaging with axial length (AL) and AL growth in preterm infants METHODS: Among a subgroup of infants from the prospective BabySTEPS study who were screened for retinopathy of prematurity (ROP) and had both AL measured and OCT imaging performed, we analyzed data collected prior to 42 weeks postmenstrual age (PMA) and prior to ROP treatment. Using linear mixed effects models, we evaluated associations between AL and AL growth with gestational age (GA), birthweight, PMA, sex, race, multiparity, maximum ROP stage, and OCT features.

RESULTS

We included 66 infants (132 eyes), mean GA = 27.6 weeks (SD = 2.3; range: 23.0-34.4) and mean birthweight = 961 g (SD = 269, range: 490-1580). In the final predictive model, longer AL was associated with earlier GA, higher birthweight, later PMA, non-White race, and thicker subfoveal choroid (all p values ≤ 0.01). AL increased linearly up to 42 weeks PMA. There was no difference in AL growth rate by GA, sex, race, multiparity, maximum ROP severity, central foveal thickness, or subfoveal choroidal thickness (all p values > 0.05); but AL growth rate was slower in infants with lower birthweight (p = 0.01).

CONCLUSIONS

Among preterm infants, those with earlier GA, higher birthweight, later PMA, non-White race, and thicker subfoveal choroid had the longest AL. AL increased linearly up to 42 weeks PMA and lower birthweight was associated with slower AL growth. These findings may improve the accuracy of measurements taken on preterm infants using imaging techniques affected by AL (e.g., measuring lateral dimensions on OCT).

TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02887157 , date of registration: August 25, 2016.

Choroidal Thickness by Handheld Swept-Source Optical Coherence Tomography in Term Newborns

Purpose

To describe normative values for choroidal thickness in newborns and characterize their relationship to vitreoretinal features.

Methods

Term newborns underwent awake, handheld swept-source optical coherence tomography (SS-OCT) in this prospective cohort study. An automated segmentation algorithm followed by manual adjustments measured choroidal thickness at the fovea and five perifoveal locations. Two masked, trained graders, with a third mediating disagreements, analyzed scans for vitreoretinal findings. OCT vitreoretinal findings, including dome-shaped macula, subretinal fluid, punctate hyperreflective vitreous opacities, persistent inner retinal layers, foveal ellipsoid zone, tractional and non-tractional vitreous bands, epiretinal membrane, cystoid macular edema, vessel elevation, scalloped retinal layers, hyporeflective vessels, and retinal spaces, were assessed and correlated with foveal choroidal thickness using a generalized linear mixed model.

Results

Fifty-nine eyes of 39 infants (mean gestational age, 39.5 weeks; 18 male, 46%) were included. Mean foveal choroidal thickness was 455.5 ± 93.9 µm. Choroid was thinner inferonasally (343.6 ± 106.2 µm) compared to superonasally (368.4 ± 92.9 µm; P = 0.03) and superotemporally (369.6 ± 100.6 µm; P = 0.02). Thinner foveal choroidal thickness was associated with absence of a foveal ellipsoid zone (437.1 ± 78.5 µm vs. 553.7 ± 93.9 µm; P = 0.02). Choroidal thickness was not significantly associated with other OCT findings.

Conclusions

We identified an association between thinner choroid and foveal immaturity. Additional study is needed to determine whether choroidal development impacts visual outcomes.

Translational Relevance

Handheld SS-OCT achieved normative measurements for choroidal thickness across the macula in term newborns, providing a foundation for future investigations into the role of choroidal development in infancy.

Retinal choroidal and retinal nerve fiber layer thickness in former preterm and full-term infants aged 4 to 8 years

PURPOSE

To compare the retinal thickness at the fovea center, peripapillary retinal nerve fiber layer (RNFL) thickness and choroidal thickness (CT) in former preterm and full-term infants.

METHODS

A total of 121 healthy children aged 4-8 years were divided 4 groups: group 1; children born on time, group 2; preterm children without a history of retinopathy of prematurity (ROP), group 3; preterm children with a history of spontaneously regressed ROP and group 4; preterm children who underwent diode laser photocoagulation for ROP. The retinal thickness at the fovea, peripapillary RNFL thickness at global, superior, inferior, nasal and temporal quadrants and submacular CT at 7 different points were measured by using spectral-domain optical coherence tomography.

RESULTS

The mean retinal thickness at the fovea center was statistically higher, whereas the mean RNFL thickness values in global, nasal, superior and inferior quadrants were statistically lower in group 4. No difference was found in the mean submacular CT value of any point between the groups.

CONCLUSION

Transpupillary diode laser photocoagulation treatment for ROP seems to cause an increase in macular thickness and a decrease in RNFL thickness.

Macular OCT Characteristics at 36 Weeks' Postmenstrual Age in Infants Examined for Retinopathy of Prematurity

PURPOSE

To report our ability to capture,-grade reliably, and analyze bedside macular OCT images from preterm infants and relate OCT findings to biological factors and retinopathy of prematurity (ROP) status at a single time window in the Study of Eye Imaging in Preterm Infants (BabySTEPS).

DESIGN

Prospective, observational study.

PARTICIPANTS

Preterm infants eligible for ROP screening with parental consent for research and a 36 ± 1 weeks' postmenstrual age (PMA) visit.

METHODS

We imaged both eyes of preterm infants with an investigational noncontact, handheld swept-source (SS) OCT at the time of clinical ROP examinations. Macular OCT features and layer thicknesses for untreated eyes of infants at 36 ± 1 weeks' PMA were compared with demographic data and clinical ROP examination performed by experts. Statistical analyses accounted for the use of both eyes of infants.

MAIN OUTCOME MEASURES

Macular OCT features and layer thicknesses, gender, race or ethnicity, gestational age, birth weight, ROP stage, and plus disease.

RESULTS

We captured macular OCT from 169 eyes (1 eye excluded because of prior ROP treatment) at 36 ± 1 weeks' PMA. The quality of OCT volumes was excellent in 33 eyes (19%), acceptable in 112 eyes (67%), poor in 24 eyes (14%), and unusable in 0 eyes (0%). Macular edema was present in 60% of eyes and was bilateral in 82% of infants with edema. At the fovea, retinal and inner nuclear layer thickness increased with edema severity: 183 ± 36 μm and 51 ± 27 μm in mild (16% of eyes), 308 ± 57 μm and 163 ± 53 μm in moderate (25%), and 460 ± 76 μm and 280 ± 83 μm in severe edema (12%), respectively. With an increase in ROP stage from 0 to 2, the mean ± standard deviation retinal thickness at the fovea increased from 227± 124 μm to 297 ± 99 μm (P < 0.001). The choroid was thinner, 155 ± 72 μm, with preplus or plus disease versus without, 236 ± 79 μm (P = 0.04), whereas retinal thickness did not vary.

CONCLUSIONS

We demonstrated the reliability of methods and the prevalence of OCT findings in preterm infants enrolled in BabySTEPS at a single time point of 36 ± 1 weeks' PMA. Variations in layer thicknesses in infants at this time point may reflect abnormalities resulting from delay in foveal development that may be impacted by macular edema, ROP, or both.

Auto-Processed Retinal Vessel Shadow View Images From Bedside Optical Coherence Tomography to Evaluate Plus Disease in Retinopathy of Prematurity

Purpose

To describe the creation of en face retinal vessel shadow view (RVSV) optical coherence tomography (OCT) images and assess the feasibility of using these for evaluating vascular disease in preterm infants at risk for retinopathy of prematurity (ROP).

Methods

In this exploratory study, we selected images from eyes with a range of ROP vascular disease, prospectively acquired from preterm infants using an investigational, noncontact, handheld, bedside swept-source OCT. We autosegmented OCT volumes using custom infant-specific software, extracted RVSV-OCT images from volumetric data bracketed around the retinal pigment epithelium, and automontaged the resulting RVSV-OCT images. Three masked ophthalmologists graded the RVSV-OCT montages as plus, pre-plus, or neither and ranked them by relative vascular disease severity.

Results

We selected images from 17 imaging sessions (7 plus, 4 pre-plus, 6 neither on clinical examination). On review, 15/17 (88%) RVSV-OCT montages were gradable for plus, pre-plus, or neither and all 17 montages were rankable for relative severity. Intergrader agreement for plus, pre-plus, or neither grading was good (κ, 0.67; 95% confidence interval, 0.42–0.86) and for relative severity ranking was excellent (intraclass correlation coefficient, 0.98; 95% confidence interval, 0.96–0.99).

Conclusions

Our novel automatic processing method can create RVSV-OCT montages optimized for retinal vessel visualization for ROP screening. Although our data support the feasibility of using RVSV-OCT montages for ranking relative vascular disease severity, there is room for improved OCT image capture and processing methods in preterm infants screened for ROP.

Translational Relevance

Creation and grading of RVSV-OCT images could eventually be integrated into an alternative method for ROP screening.

Choroidal thickness and ocular growth in childhood

The involvement of the choroid in ocular growth regulation has been postulated in studies showing that refractive errors correlate with alterations in choroidal thickness (ChT). The advent of optical coherence tomography imaging has enabled qualitative and quantitative assessment of the choroid. In children, ChT changes correlate with a number of ocular pathologies, including myopia, retinopathy of prematurity, and amblyopia. We synthesize mechanisms and evidence regarding choroidal thickness variation during childhood. Subfoveal ChT is influenced by a number of factors including age, ethnicity, gender, axial length, and intraocular pressure. Myopic eyes have thinner choroids compared to emmetropic and hyperopic eyes. ChT may in fact serve as a marker of myopic progression, as ChT thinning occurs early during myopic development, but this association has not been established quantitatively. In addition, subfoveal ChT appears thicker in amblyopic eyes, while prematurity and retinopathy of prematurity may be associated with thinner ChT. Overall, both animal models and clinical research indicate that ChT induces or reflects physiological changes in the eye pertaining to ocular growth or maturation.

Prospective Longitudinal Evaluation of the Peripheral Choroidal Thickness in High-Risk Infants with Retinopathy of Prematurity: A Pilot Study

Objective

The purpose of this study was to prospectively follow up the peripheral choroidal development and thickness for retinopathy of prematurity (ROP) in high-risk premature infants using optic coherence tomography.

Materials and Methods

All infants included in the analysis had an optical coherence tomography (OCT) evaluation, serially over 6 weeks, starting at the first ROP screening exam and at each follow-up screening exam. We included infants born at or earlier than 25 weeks of gestation, weighing less than 700 grams, and those who developed interventricular hemorrhage. We evaluated the choroidal thickness and development, centrally and at the extreme nasal and temporal periphery, for each eye with each ROP screening exam. Changes in the choroidal thickness and the choroidal thickness to retinal thickness ratio (C/R ratio) were evaluated over time not only for each individual infant, but between the infants as well.

Results

Six infants met our inclusion criteria. Infants with severe ROP had a mean choroidal thickness that was significantly thinner in the extreme temporal periphery than infants that did not develop significant ROP (P=0.02). The mean value of the C/R ratio was smaller in infants with severe ROP compared to those that did not develop any significant ROP at any of the evaluated locations (P < 0.001).

Conclusion

The peripheral choroid appears to be significantly thinner relative to the retinal thickness in infants with severe ROP.

Experimental Evidence Behind Clinical Trial Outcomes in Retinopathy of Prematurity

Treatment of severe retinopathy of prematurity (ROP) has evolved over the last decade. This article reviews recent clinical trials and experimental evidence that supports clinical outcomes and observations, including the efficacy of anti-vascular endothelial growth factor (VEGF) agents in reducing the vascular activity of severe ROP, and the mechanisms behind recurrent stage 3 ROP and plus disease in some infants treated with anti-VEGF agents. Also discussed will be current imaging modalities that link experimental models of ROP with longitudinal human studies and which provide exciting future opportunities to enhance the understanding of pathophysiology of ROP and improve treatments. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:228-234.].

Changes in choroidal thickness in healthy pediatric individuals: a longitudinal study

AIM

To investigate the changes in the choroidal thickness in healthy pediatric children in a longitudinal study, and to determine the ocular and systemic parameters that were significantly correlated with the changes in the choroidal thickness.

METHODS

This study included 64 eyes of 34 healthy Japanese children with a mean age (±SD) of 4.4 (±0.4)y (range, 3.6-5.8y) at baseline. Swept-source optical coherence tomography (SS-OCT) was used to record images of the retina and choroid at the baseline and after a mean follow-up period of about 1.5y. The 3D raster scan protocol was used to construct the choroidal thickness map. Mean choroidal thickness was calculated for each of the nine sectors of the Early Treatment Diabetic Retinopathy Study grid. Best-corrected visual acuity, axial length, body height, and weight were also measured. Changes in measurements were defined as the baseline values subtracted from the values at the final visit. A generalized estimating equation was used to eliminate the effect of within-subject intereye correlations.

RESULTS

The mean central choroidal thickness was significantly reduced during the follow-up period (baseline, 301.8±8.6 µm; final visit, 286.6±8.0 µm, P<0.001). The decrease in the choroidal thickness was greatest in the central sector, followed by the sectors of the inner and outer rings. The inner and outer rings had diameters of 1 to 3 mm and 3 to 6 mm, respectively. The changes in the choroidal thickness in the central, inner ring, and outer ring sectors were significantly and negatively correlated with the age, baseline body height, baseline body weight, and elongation of the axial length.

CONCLUSION

These results indicate that the choroidal thickness among preschool-aged Japanese children decreased significantly during the follow-up period. The choroidal thinning is significantly associated with the elongation of axial length. These characteristics should be considered in the evaluation of choroidal thickness in younger children with retinochoroidal disorders.

An automated method for choroidal thickness measurement from Enhanced Depth Imaging Optical Coherence Tomography images

The choroid is vascular tissue located underneath the retina and supplies oxygen to the outer retina; any damage to this tissue can be a precursor to retinal diseases. This paper presents an automated method of choroidal segmentation from Enhanced Depth Imaging Optical Coherence Tomography (EDI-OCT) images. The Dijkstra shortest path algorithm is used to segment the choroid-sclera interface (CSI), the outermost border of the choroid. A novel intensity-normalisation technique that is based on the depth of the choroid is used to equalise the intensity of all non-vessel pixels in the choroid region. The outer boundary of choroidal vessel and CSI are determined approximately and incorporated to the edge weight of the CSI segmentation to choose optimal edge weights. This method is tested on 190 B-scans of 10 subjects against choroid thickness (CTh) results produced manually by two graders. For comparison, results obtained by two state-of-the-art automated methods and our proposed method are compared against the manual grading, and our proposed method performed the best. The mean root-mean-square error (RMSE) for finding the CSI boundary by our method is 7.71±6.29 pixels, which is significantly lower than the RMSE for the two other state-of-the-art methods (36.17±11.97 pixels and 44.19±19.51 pixels). The correlation coefficient for our method is 0.76, and 0.51 and 0.66 for the other two state-of-the-art methods. The interclass correlation coefficients are 0.72, 0.43 and 0.56 respectively. Our method is highly accurate, robust, reliable and consistent. This identification can enable to quantify the biomarkers of the choroidin large scale study for assessing, monitoring disease progression as well as early detection of retinal diseases. Identification of the boundary can help to determine the loss or change of choroid, which can be used as features for the automatic determination of the stages of retinal diseases.

Changes in Relative Position of Choroidal Versus Retinal Vessels in Preterm Infants

Purpose

The purpose of this study was to characterize a novel finding that relative positions of choroidal and retinal vessels change over time in preterm infants and to identify factors associated with this finding using quantitative analysis.

Methods

Fundus images were obtained prospectively through a retinopathy of prematurity (ROP) cohort study. Images were excluded if choroidal vessels could not be identified. Changes in relative position of characteristic choroidal landmarks with respect to retinal vessels between two time points 5 to 7 weeks apart were measured. Univariate and multivariate regression analyses were performed to identify associated factors with the amount of change.

Results

The discovery and replication cohorts included 45 and 58 patients, respectively. Ninety-two of them (89%) were non-Hispanic Caucasians. Changes in relative position of choroidal versus retinal vessels were detected in all eyes of the discovery and replication cohorts (mean amount = 0.42 ± 0.12 and 0.35 ± 0.12 mm, respectively). On combined multiple regression analysis of the two cohorts, type 1 ROP, higher postmenstral age at the first time point, and shorter distance from optic disc to choroidal landmark were significantly associated with less change in relative position.

Conclusions

Choroidal vessels grow anteriorly with respect to retinal vessels at posterior pole in preterm infants, suggesting relatively faster peripheral growth of choroidal versus retinal vessels. Eyes with severe ROP showed less difference in growth, which might represent alterations in choroidal development due to advanced ROP. These findings may contribute to better understanding about the physiology of choroidal development and involvement in ROP.

Retinopathy of prematurity: inflammation, choroidal degeneration, and novel promising therapeutic strategies

Retinopathy of prematurity (ROP) is an important cause of childhood blindness globally, and the incidence is rising. The disease is characterized by initial arrested retinal vascularization followed by neovascularization and ensuing retinal detachment causing permanent visual loss. Although neovascularization can be effectively treated via retinal laser ablation, it is unknown which children are at risk of entering this vision-threatening phase of the disease. Laser ablation may itself induce visual field deficits, and there is therefore a need to identify targets for novel and less destructive treatments of ROP. Inflammation is considered a key contributor to the pathogenesis of ROP. A large proportion of preterm infants with ROP will have residual visual loss linked to loss of photoreceptor (PR) and the integrity of the retinal pigment epithelium (RPE) in the macular region. Recent studies using animal models of ROP suggest that choroidal degeneration may be associated with a loss of integrity of the outer retina, a phenomenon so far largely undescribed in ROP pathogenesis. In this review, we highlight inflammatory and neuron-derived factors related to ROP progression, as well, potential targets for new treatment strategies. We also introduce choroidal degeneration as a significant cause of residual visual loss following ROP. We propose that ROP should no longer be considered an inner retinal vasculopathy only, but also a disease of choroidal degeneration affecting both retinal pigment epithelium and photoreceptor integrity.

CHOROIDAL THICKNESS IN HEALTHY CHINESE CHILDREN AGED 6 to 12: The Shanghai Children Eye Study

PURPOSE

To explore the characteristics of choroidal thickness (ChT) in Chinese children.

METHODS

A total of 144 healthy children, aged 6 years to 12 years old, were enrolled in the study. The ChT of subfovea and peripheral locations 0.5, 1.5, and 2.5 mm away from the fovea were evaluated by enhanced depth imaging optical coherence tomography. The association between subfoveal ChT and systemic, as well as ocular factors, including age, sex, height, weight, body mass index, axial length, refractive error, intraocular pressure, preterm history, and the refractive status of parents were studied.

RESULTS

The mean subfoveal ChT was 302 ± 63 μm. In the nasal, superior, and inferior areas, the ChT of locations closer to the fovea was thicker than those farther away from the fovea (all P < 0.05); however, ChT was not significantly different among different locations in the temporal area (P = 0.16). The ChT of the nasal quadrant was significantly thinner than that of other areas (P < 0.01). Subfoveal ChT decreased with age, axial length, preterm history, and increased with height. Sex was not statistically associated with subfoveal ChT.

CONCLUSION

In Chinese children, the ChT is thinnest in the nasal quadrant and thicker in central regions than in peripheral areas. The subfoveal ChT independently decreases with age, axial length, preterm history, and increases with height.

Macular morphology in former preterm and full-term infants aged 4 to 10 years

OBJECTIVE

To analyse macular retinal and choroidal layer thickness in former preterm and full-term infants and to assess associated perinatal influence factors and functional correlation.

METHODS

This prospective controlled, cross-sectional, hospital-based study in a tertiary center of maximum care examined former preterm infants with a gestational age (GA) ≤ 32 weeks and full-term neonates currently aged 4 to 10 years. We investigated data from 397 infants, analysing total foveal retinal thickness and six distinct macular retinal layer and choroidal layer measurements via spectral-domain optical coherence tomography. Multivariable linear regression analysis was performed to investigate associations of layer thickness with GA and retinopathy of prematurity (ROP).

RESULTS

Total retinal thickness in the fovea was thicker in former preterm infants with GA ≤ 28 weeks and in those with GA between 29-32 weeks compared to full-term infants independently of ROP. Occurrence of ROP was also associated with increased foveal thickness. Ganglion cell layer together with inner plexiform layer (GCL+IPL) was thinner in infants with GA ≤ 28 weeks than in full-term infants at 1000 and 2000μm distance from the fovea, but no association with ROP was present. Similar results were found for the photoreceptor layer. Total foveal retinal thickness was associated with low visual function.

CONCLUSION

This study identified low gestational age and ROP occurrence as main determinants for foveal thickening. Furthermore, thinned GCL+IPL measurements were associated with lower gestational age. This study highlights the prognostic value of these maturity parameters influencing retinal morphology, which may affect visual function.

CHOROIDAL THICKNESS IN INFANTS WITH RETINOPATHY OF PREMATURITY

PURPOSE

To evaluate choroidal thickness in premature infants and its relationship with stage of retinopathy of prematurity (ROP) using spectral domain optical coherence tomography (SD-OCT).

METHODS

Spectral domain optical coherence tomography imaging for measuring subfoveal choroidal thickness was performed for 80 premature infants. Subfoveal choroidal thickness was defined as the distance from the hyperreflective line of the outermost retinal pigment epithelium (RPE) to the innermost hyperreflective line of the choroidoscleral junction. Each measurement was performed at the central fovea (CF) and 0.75 mm to 1.5 mm nasal (N1 and N2) and temporal (T1 and T2) to the fovea. Subfoveal choroidal thickness and grading of cystoid macular edema (CME) were analyzed statistically.

RESULTS

Choroidal thickness of CF was found to be significantly greater than nasal (N1 and N2) and temporal (T1 and T2) choroidal thickness (P < 0.05). There was no significant relationship between stage of ROP and nasal (N1 and N2) choroidal thickness (P = 0.057, P = 0.282, respectively). However, CF and temporal (T1 and T2) choroidal thickness was found to be significantly lower at a higher stage of ROP (P = 0.005, P = 0.01 and P = 0.001). No significant relationship was found between subfoveal choroidal thickness and the grades of cystoid macular edema (P > 0.05). The choroidal thickness of CF was found to be correlated with birth weight (r = 0.267, P = 0.017) but not birth week (r = 0.140, P = 0.217). Maximum stage of ROP was found to be negatively correlated with choroidal thickness, at N1, T1, and T2 (r < -0.250, P < 0.02).

CONCLUSION

The subfoveal choroid in premature infants can be effectively evaluated using a portable SD-OCT device. Choroidal thickness gets thinner with the severity of ROP and the decrease is more prominent at the central and temporal location. Cystoid macular edema is not correlated with choroidal thickness in premature infants.

Review of the mechanisms and therapeutic avenues for retinal and choroidal vascular dysfunctions in retinopathy of prematurity

Retinopathy of prematurity (ROP) is a multifactorial disease and the main cause of visual impairment and blindness in premature neonates. The inner retina has been considered the primary region affected in ROP, but choroidal vascular degeneration and progressive outer retinal dysfunctions have also been observed. This review focuses on observations regarding neurovascular dysfunctions in both the inner and outer immature retina, the mechanisms and the neuronal-derived factors implicated in the development of ROP, as well potential therapeutic avenues for this disorder.

CONCLUSION

Alterations in the neurovascular integrity of the inner and outer retina contribute to the development of ROP.

Foveal Layer Morphology Detected on Spectral Domain Optical Coherence Tomography and its Correlation with Visual Acuity in Asian Indian Premature Infants in their First Year of Life

PURPOSE

To report foveal microanatomy imaged on handheld spectral domain optical coherence tomography (SDOCT) and correlate it with visual acuity in Asian Indian premature infants.

METHODS

A retrospective analysis of 32 Asian Indian premature infants, 10 with Type 2 retinopathy of prematurity (ROP), were imaged between 3 and 12 months of corrected postmenstrual age (PMA) on the handheld SDOCT (Envisu 2300, Bioptigen, DNC, USA). The foveal findings on these images were correlated with visual acuity measured using Teller acuity cards. The study cohort was divided into three groups based on the corrected age, 3-<6 months, 6-<9 months, and 9-12 months. SDOCT images of the foveal center were analyzed for inner retinal layer (IRL) persistence or fusion and presence of the external limiting membrane (ELM), inner segment-outer segment or the ellipsoid zone (EZ), and the outer segment-retinal pigment epithelium (OS-RPE) layers.

RESULTS

The mean visual acuity of the three groups was 1.60, 1.63, and 1.23 logMAR, respectively (p < 0.001). Visual acuity significantly correlated with all four layers (IRL fusion, ELM, EZ, and OS-RPE in the 3-<6-month group [p < 0.001], IRL fusion only in 6-<9-month group (p < 0.001), and IRL fusion and EZ in the 9-12-month group (p < 0.001 and p = 0.01, respectively).

CONCLUSIONS

The study provides insights into our understanding of a premature infant's foveal maturation in the first year. Inner retinal fusion or maturation is the most important event that correlates with better visual acuity throughout the first year. In addition, between 9 and 12 months PMA, the completion of the EZ at the foveal center positively influenced visual acuity. The presence of ROP did not influence development of the layers, but the sample size was small for subgroup analysis.

FUNCTIONAL OUTCOMES OF YOUNG INFANTS WITH AND WITHOUT MACULAR EDEMA

PURPOSE

The authors relate posterior segment microanatomy from perinatal spectral domain optical coherence tomography to visual acuity, brain abnormalities, and neurodevelopment.

METHODS

Thirteen infants (11 preterm and 2 term birth), imaged in the nursery with portable spectral domain optical coherence tomography, had visual acuity and sensorimotor testing at age 9 months to 15 months (grating acuity) or 4 years to 5 years (optotype), and medical records reviewed for brain magnetic resonance imaging reports and Bayley scales testing at age 18 months to 24 months.

RESULTS

Eight children with age-appropriate macular microanatomy without edema on perinatal spectral domain optical coherence tomography had optimal (≥ 20/40) or within normal limits (grating acuity) visual acuity. Five children with perinatal macular edema had suboptimal visual acuity (in 9/10 eyes) and sensorimotor deficits, magnetic resonance imaging abnormalities, or poor neurodevelopment. Macular edema persisted in 1 infant through 9-month corrected age.

CONCLUSION

Maturation of the visual system and evolution of retinal anomalies can be monitored with posterior segment spectral domain optical coherence tomography. Retinal microanatomy observed in infancy might relate to subsequent vision and other central nervous system events, but additional studies are needed to determine the range of normal microanatomy in infants and how this relates to vision and neurodevelopment.

Retinal Imaging of Infants on Spectral Domain Optical Coherence Tomography

Spectral domain coherence tomography (SD OCT) has become an important tool in the management of pediatric retinal diseases. It is a noncontact imaging device that provides detailed assessment of the microanatomy and pathology of the infant retina with a short acquisition time allowing office examination without the requirement of anesthesia. Our understanding of the development and maturation of the infant fovea has been enhanced by SD OCT allowing an in vivo assessment that correlates with histopathology. This has helped us understand the critical correlation of foveal development with visual potential in the first year of life and beyond. In this review, we summarize the recent literature on the clinical applications of SD OCT in studying the pathoanatomy of the infant macula, its ability to detect subclinical features, and its correlation with disease and vision. Retinopathy of prematurity and macular edema have been discussed in detail. The review also summarizes the current status of SD OCT in other infant retinal conditions, imaging the optic nerve, the choroid, and the retinal nerve fibre in infants and children, and suggests future areas of research.

[Analysis of choroidal thickness in AP-ROP, threshold disease and ROP without laser photocoagulation]

BACKGROUND

Enhanced depth imaging (EDI) and spectral domain optical coherence tomography (SD-OCT) provide high-definition cross-sectional images of the choroid. Information on alterations in choroidal thickness (CT) after laser photocoagulation (LC) in aggressive posterior retinopathy of prematurity (APROP) and threshold disease (TD) is rare.

PATIENTS AND METHODS

A total of 75 eyes were retrospectively analyzed in 4 groups. Groups 1 and 2 included patients with APROP and TD, respectively, who underwent LC. Group 3 included ROP children who did not undergo LC and group 4 included full-term children. Infants aged ≥4 < 7, who had examination of subfoveal (SF) CT with SD-EDI-OCT, visual acuity (VA), spherical equivalent (SE), anterior segment and fundus examination, axial lenght (AXL) were included. The results of SFCT, VA and SE at the age of ≥ 4 < 7 years, AXL, gestational age (GA), birth weight (BW) and age at examination were compared between the groups. Potential risk factors (GA, BW, SE, AXL and SFCT) influencing visual acuity were evaluated by using multivariate linear regression analysis.

RESULTS

The results of SFCT and AXL were not significantly different between groups 2 and 3 or between groups 3 and 4. There was a significant difference between the other groups for SFCT and AXL and VA was significantly different between all groups. The SE was not significantly different between groups 3 and 4 but there was a significant difference for SE, BW and GA between the groups. Age at examination was not significantly different between the groups. Multivariate linear regression analysis revealed SFCT for groups 1 and 2, GA for group 3 and GA, SFCT and AXL for group 4 as independent risk factors influencing visual acuity.

CONCLUSION

The regression model used for groups 1-4 explains the variation of the dependent risk factor LogMar VA for groups 1-4 with 31.2 %, 43.5 %, 9.6 % and 69.4 %, respectively. These values expressed in percentage demonstrate that even more predictors may influence the dependent factor LogMar VA than evaluated in the study.

Automated choroid segmentation based on gradual intensity distance in HD-OCT images

The choroid is an important structure of the eye and plays a vital role in the pathology of retinal diseases. This paper presents an automated choroid segmentation method for high-definition optical coherence tomography (HD-OCT) images, including Bruch's membrane (BM) segmentation and choroidal-scleral interface (CSI) segmentation. An improved retinal nerve fiber layer (RNFL) complex removal algorithm is presented to segment BM by considering the structure characteristics of retinal layers. By analyzing the characteristics of CSI boundaries, we present a novel algorithm to generate a gradual intensity distance image. Then an improved 2-D graph search method with curve smooth constraints is used to obtain the CSI segmentation. Experimental results with 212 HD-OCT images from 110 eyes in 66 patients demonstrate that the proposed method can achieve high segmentation accuracy. The mean choroid thickness difference and overlap ratio between our proposed method and outlines drawn by experts was 6.72µm and 85.04%, respectively.

Applications of optical coherence tomography in pediatric clinical neuroscience

For nearly two centuries, the ophthalmoscope has permitted examination of the retina and optic nerve-the only axons directly visualized by the physician. The retinal ganglion cells project their axons, which travel along the innermost retina to form the optic nerve, marking the beginning of the anterior visual pathway. Both the structure and function of the visual pathway are essential components of the neurologic examination as it can be involved in numerous acquired, congenital and genetic central nervous system conditions. The development of optical coherence tomography now permits the pediatric neuroscientist to visualize and quantify the optic nerve and retinal layers with unprecedented resolution. As optical coherence tomography becomes more accessible and integrated into research and clinical care, the pediatric neuroscientist may have the opportunity to utilize and/or interpret results from this device. This review describes the basic technical features of optical coherence tomography and highlights its potential clinical and research applications in pediatric clinical neuroscience including optic nerve swelling, optic neuritis, tumors of the visual pathway, vigabatrin toxicity, nystagmus, and neurodegenerative conditions.

Assessment of retinal nerve fiber layer thickness in healthy, full-term neonates

PURPOSE

To measure average retinal nerve fiber layer (RNFL) thicknesses in healthy, full-term neonates.

DESIGN

Descriptive research to develop normative data.

METHODS

Healthy infants born between 37 and 42 weeks postmenstrual age were imaged with hand-held spectral-domain optical coherence tomography. A custom script segmented the RNFL; the fovea and optic nerve center were manually selected. A second script measured the average RNFL thickness along the papillomacular bundle, defined as the arc from -15 degrees to +15 degrees on the axis from the optic nerve to fovea, with radii of 1.1, 1.3, 1.5, and 1.7 mm from the center of the optic disc. Shapiro-Wilk W tests assessed these measurements for normality to determine the age-appropriate radial distance for subsequent analyses. Average RNFL thicknesses for four temporal 45-degree sectors (superior temporal, temporal superior, temporal inferior, and inferior temporal) and the temporal quadrant were calculated and compared to demographic parameters for all infants.

RESULTS

Fifty full-term infants were adequately imaged for RNFL analysis. RNFL thicknesses at 1.5 mm radial distance from the optic nerve were the most normally distributed. While there was a trend toward greater mean superior temporal RNFL thickness for both black and Hispanic vs white infants (128 ± 27 μm, 124 ± 30 μm, and 100 ± 19 μm, respectively, P = .04 for both comparisons), there were no other significant differences noted in RNFL thicknesses by race, sex, gestational age, or birth weight.

CONCLUSIONS

We present RNFL thickness measurements for healthy, full-term infants that may serve as normative data for future analyses.

Interocular symmetry in macular choroidal thickness in children

Objective. To report interocular differences in choroidal thickness in children using spectral domain optical coherence tomography (SD-OCT) and correlate findings with biometric data. Methods. This observational cross-sectional study included 91 (182 eyes) healthy children aged 6 to 17 years with no ocular abnormality except refractive error. After a comprehensive eye exam and axial length measurement, high definition macular scans were performed using SD-OCT. Two observers manually measured the choroidal thickness at the foveal center and at 1500 µm nasally, temporally, inferiorly, and superiorly. Interocular differences were computed; correlations with age, gender, refractive error, and axial length were performed. Results. Mean age was 10.40 ± 3.17 years; mean axial length and refractive error values were similar between fellow eyes. There was excellent correlation between the two observers' measurements. No significant interocular differences were observed at any location. There was only a trend for right eyes to have higher values in all thicknesses, except the superior thickness. Most of the choroidal thickness measurements correlated positively with spherical equivalent but not with axial length, age, or gender. Conclusion. Choroidal thickness measurements in children as performed using SD-OCT revealed a high level of interobserver agreement and consistent interocular symmetry. Values correlated positively with spherical equivalent refraction.

Poorer neurodevelopmental outcomes associated with cystoid macular edema identified in preterm infants in the intensive care nursery

PURPOSE

To evaluate the association between cystoid macular edema (CME) observed in very preterm infants and developmental outcomes at 18 to 24 months corrected age.

DESIGN

Cohort study.

PARTICIPANTS

Infants born at or less than 1500 g or at or less than 30 weeks postmenstrual age who underwent screening for retinopathy of prematurity (ROP) in an intensive care nursery.

METHODS

Bedside handheld spectral-domain optical coherence tomography (SD OCT; Envisu, Bioptigen, Inc, Research Triangle Park, NC) imaging was obtained from preterm infants who were being screened for ROP and graded for presence of CME, central foveal thickness (CFT), inner nuclear layer thickness, and foveal-to-parafoveal thickness ratio. At 18 to 24 months corrected age, the children were assessed with the Bayley Scales of Infant and Toddler Development, Third Edition.

MAIN OUTCOME MEASURES

Scores on the Bayley cognitive, language, and motor subscales.

RESULTS

Among 77 children with SD OCT imaging, 53 were evaluated with the Bayley Scales. Compared with children who did not have CME as infants (n=22), the mean score for children who had CME (n=31) was 7.3 points (95% confidence interval [CI], -15.5 to 0.9; P=0.08) lower on the cognitive subscale, 14.1 points (95% CI, -22.7 to -5.5; P=0.002) lower for the language subscale, and 11.5 points (95% CI, -21.6 to -1.3; P=0.03) lower for the motor subscale. Differences were maintained after adjusting for gestational age and birth weight. Severity of CME, as assessed by foveal-to-parafoveal thickness ratio, within the CME group correlated with poorer cognitive (R2=0.16, P=0.03) and motor (R2=0.15, P=0.03) development.

CONCLUSIONS

Cystoid macular edema observed on SD OCT in very preterm infants screened for ROP is associated with poorer language and motor skills at 18 to 24 months corrected age. Evaluation of the retina with SD-OCT may serve as an indicator of neurodevelopmental health for very preterm infants in the intensive care nursery.

Intra- and inter-visit reproducibility of ganglion cell-inner plexiform layer measurements using handheld optical coherence tomography in children with optic pathway gliomas

PURPOSE

To determine the intra- and inter-visit reproducibility of ganglion cell-inner plexiform layer thickness measures using handheld optical coherence tomography (OCT) in sedated children with optic pathway gliomas and/or neurofibromatosis type 1 (NF1).

DESIGN

Prospective longitudinal cohort study.

METHODS

Children with sporadic optic pathway gliomas and/or NF1 who had ≥2 volumes acquired over the macula using handheld OCT during sedation for clinically indicated magnetic resonance imaging were eligible for the intra-visit cohort. Children with repeat handheld OCT imaging within 6 months were eligible for the inter-visit cohort. Total retinal thickness and ganglion cell-inner plexiform layer thickness were measured using custom-designed automated segmentation software. Reproducibility was compared across average and anatomic quadrant by calculating the coefficient of variation (CV) and intraclass correlation coefficient (ICC).

RESULTS

Forty-two subjects (median age 5.4 years, range 0.8-12.7 years) contributed 45 eyes to the intra-visit cohort. Thirty-one subject eyes had normal vision and 14 had abnormal vision (decreased visual acuity and/or visual field). Average and quadrant ganglion cell-inner plexiform layer measures demonstrated CVs ≤4.5% with excellent ICCs (>0.935). The superior quadrant CV differed between subjects with (4.4%) and without (2.1%) vision loss (P < .05). Twenty-five subject eyes were eligible for the inter-visit cohort, demonstrating CVs from 1.6% to 5.2%. Inter-visit ICCs were excellent (0.955-0.995).

DISCUSSION

Handheld OCT imaging in sedated children with optic pathway gliomas produces highly reproducible measures of ganglion cell-inner plexiform layer thickness.

Association of choroidal thickness with eye growth: a cross-sectional study of individuals between 4 and 23 years

BACKGROUND AND AIMS

We aimed to evaluate the association of subfoveal choroidal thickness (SFCT) with age and to determine its relationship with axial length (AL) and ocular biometric parameters, in children and young adults during growth period.

METHODS

One hundred and sixty patients (80 male, 80 female) aged between 4 and 23 years were included. Patients were classified into five groups according to their ages as group 1 (4-7 years of age), group 2 (8-11 years), group 3 (12-15 years), group 4 (16-19 years), and group 5 (20-23 years). SFCT was assessed using spectral-domain optical coherence tomography (3D OCT-2000). The measurements were taken at the same daytime (1000-1200 hours) to avoid diurnal fluctuation. Ocular AL and anterior segment parameters were measured using optical biometry (Lenstar LS900)).

RESULTS

The average SFCT was 308.1±47.6 μm, ranging from 206 to 410 μm. The mean SFCT values in group 1 to 5 were measured as 306.8±42.0, 297.8±48.1, 283.2±38.9, 326.9±57.4, and 325.8±35.9 μm, respectively. The mean CT of group 3 was significantly thinner than group 4 and 5 (P<0.05 for two groups), however, there was no statistical significance compared with group 1 (P=0.227) and group 2 (P=0.693). On stepwise regression analysis, age exhibited a positive association with SFCT (B=2.8, P<0.001) and AL exhibited a negative association with choroidal thickness (B=-16.7, P<0.001).

CONCLUSIONS

We found that SFCT shows no age-related difference until age of 15, whereas 16-23-year old participants had thicker SFCT compared with the younger ones. In that aspect, a thicker choroid associated with age in certain age groups suggests an age period of SFCT increase to a plateau in young adulthood. Larger studies are warranted to elucidate the age-related changes in SFCT in childhood, as improved evaluation of normal choroidal thicknesses during eye growth should assist in the diagnosis of choroidal abnormalities associated with eye disease.

Reproducibility of circumpapillary retinal nerve fiber layer measurements using handheld optical coherence tomography in sedated children

PURPOSE

To determine the intra- and intervisit reproducibility of circumpapillary retinal nerve fiber layer (RNFL) measures using handheld optical coherence tomography (OCT) in sedated children.

DESIGN

Prospective cross-sectional and longitudinal study.

METHODS

Children undergoing sedation for a clinically indicated magnetic resonance imaging for an optic pathway glioma and/or neurofibromatosis type 1 (NF1) had multiple 6 × 6 mm volumes (isotropic 300 × 300 or nonisotropic 1000 × 100 samplings) acquired over the optic nerve. Children with 2 handheld OCT sessions within 6 months were included in the intervisit cohort. The intra- and intervisit coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated for the average and anatomic quadrant circumpapillary RNFL thickness.

RESULTS

Fifty-nine subjects (mean age 5.1 years, range 0.8-13.0 years) comprised the intravisit cohort and 29 subjects (mean age 5.7 years, range 1.8-12.7 years) contributed to the intervisit cohort. Forty-nine subjects had an optic pathway glioma and 10 subjects had NF1 without an optic pathway glioma. The CV was comparable regardless of imaging with an isotropic and nonisotropic volume in both the intra- and intervisit cohorts. The average circumpapillary RNFL demonstrated the lowest CV and highest ICC compared to the quadrants. For the intervisit cohort, the average ICC was typically higher while the CV was typically lower, but not statistically different compared to the other quadrants.

DISCUSSION

Circumpapillary RNFL measures acquired with handheld OCT during sedation demonstrate good intra- and intervisit reproducibility. Handheld OCT has the potential to monitor progressive optic neuropathies in young children who have difficulty cooperating with traditional OCT devices.

Handheld simultaneous scanning laser ophthalmoscopy and optical coherence tomography system

Scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) are widely used retinal imaging modalities that can assist in the diagnosis of retinal pathologies. The combination of SLO and OCT provides a more comprehensive imaging system and a method to register OCT images to produce motion corrected retinal volumes. While high quality, bench-top SLO-OCT systems have been discussed in the literature and are available commercially, there are currently no handheld designs. We describe the first design and fabrication of a handheld SLO/spectral domain OCT probe. SLO and OCT images were acquired simultaneously with a combined power under the ANSI limit. High signal-to-noise ratio SLO and OCT images were acquired simultaneously from a normal subject with visible motion artifacts. Fully automated motion estimation methods were performed in post-processing to correct for the inter- and intra-frame motion in SLO images and their concurrently acquired OCT volumes. The resulting set of reconstructed SLO images and the OCT volume were without visible motion artifacts. At a reduced field of view, the SLO resolved parafoveal cones without adaptive optics at a retinal eccentricity of 11° in subjects with good ocular optics. This system may be especially useful for imaging young children and subjects with less stable fixation.